docs: def extract(self, member, path=None, pwd=None):
          """Extract single file into current directory.
  
          Parameters:
  
              member
                  filename or :class:`RarInfo` instance
              path
                  optional destination path
              pwd
                  optional password to use
          """
          if isinstance(member, RarInfo):
              fname = member.filename
          else:
              fname = member
          self._extract([fname], path, pwd)